Embryos of Butia catarinensis are rudimentary and tolerant of desiccation and liquid nitrogen temperatures, but require GA3 to germinate

Palms have high ecological and economical importance in tropical and subtropical regions around the world. Preserving genetic resources of palms is hampered by poor understanding of the complex seed physiology, which differs in desiccation tolerance and germination requirements depending on species and ecoregion. This study investigates Butia catarinensis embryo water content threshold, in vitro germination using gibberellin 3 (GA 3 ) (0 and 8µM) and cryopreservation methods (cooling rate and cryoprotectant solution) for propagation and ex situ preservation of an endemic Arecaceae from Brazil. We use light and electronic microscopy to study the effect of desiccation and low temperatures in embryos cells. B. catarinensis embryos exhibit physiological and cytological traits from both, desiccations tolerant (small vacuoles, lipid and protein reserves) and sensitive (many mitochondria and endoplasmic reticulum) palms seeds. Embryos excised from mature seeds lacked differentiated cells, especially above the cotyledonary axis, but showed 90% of germination on MS medium containing 8µM of GA 3 , suggesting that B. catarinensis seeds exhibit morphophysiological dormancy. Embryos from mature fruits were quite moist (1.42 gH 2 O • gDW − 1 ). Extreme embryo dehydration to 0.13gH 2 O • gDW − 1 caused ultrastructural deformation, but did not reduce the capacity of the embryo to germinate (83%) upon rehydration. As a step toward cryobanking, embryo response to immersion in liquid nitrogen (LN) were 77% normal seedlings post-thawing and in vitro cultivation. B. catarinensis embryos are rudimentary, desiccation tolerant and can be stored in LN and revived using cryobiotechnology strategies. This can be effective at protecting genetic diversity of threatened species as B. catarinensis from anthropogenic threats. Key message Butia catarinensis embryos are rudimentary, desiccation tolerant and can be stored at liquid nitrogen temperatures and revived using cryobiotechnology strategies.